Phaseless diagnostics for non-rectangular near-field antenna measurement systems

The emergence of the near-field phaseless measurements as viable solutions to the antenna measurements at higher frequencies has created a lot of enthusiasm among the researchers. There had been an ongoing desire to enhance these techniques to a level where they can perform as accurate as the current amplitude-phase near-field techniques. The implementation of these techniques on different types of chambers might require some special treatments. In non-rectangular near-field systems such as bi-polar and plane-polar there is a need to co-rotate the probe with the antenna under test to maintain the polarization fixed. It is shown that in near-field systems if one measures two set of orthogonal data then there would be no need for the simultaneous probe co-rotation. Although there is no need for this extra motion in non-rectangular amplitude-phase near-field systems for phaseless techniques the probe co-rotation become extremely important. This paper discusses this issue and has proposed an iterative technique to alleviate this extra motion. The ability of the proposed method in diagnosing a typical aperture antenna with faulty sections is also examined through simulations.